I have never ran into as hard of a piece of steel as a kran 30/40 screw ever ever !!! I broke a screw off so I garbed a a drill to drill a hole in it so I could use a easy-out and I could not even make a mark in it .. I tried every thing cobalt titanium carbide nothing worked .. it had to be hardened to the infinity rockwell  nothing nada blaa .. So it tried a diamond drill bit and it worked took 10 minutes the only other screw I have scene came out of the Henry Ford plant in the 1920 ... Are all Krag screws this hard .. Or was it over tempered ???   

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